﻿// ———————————————————————–
// <copyright file="EventExtensions.cs" company="The MITRE Corporation">
//    Copyright (c) 2014 The MITRE Corporation. All rights reserved.
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
//    http://www.apache.org/licenses/LICENSE-2.0
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.
// </copyright>
// ———————————————————————–
/////////////////////////////////////////////////////////////////////////////////////////////////
// EventExtensions.cs:
//
// A community-specific extension to a message, for which the XML schema is not known in advance.
//
// Project: IC.NET - CAD Library
// Author:  Jim Cronin - MITRE
/////////////////////////////////////////////////////////////////////////////////////////////////

// Copyright (c) 2014 The MITRE Corporation. All rights reserved.
//
// NOTICE
// This software was produced for the U. S. Government
// under Contract No. FA8721-09-C-0001, and is
// subject to the Rights in Noncommercial Computer Software
// and Noncommercial Computer Software Documentation Clause
// (DFARS) 252.227-7014 (JUN 1995)

using System;
using System.Collections.Generic;
using System.Xml;

namespace EDXLSharp.NIEMCADLib
{
  /// <summary>
  /// A community-specific extension to a message, for which the
  /// XML schema is not known in advance.
  /// </summary>
  public class EventExtensions : IComposable
  {
    public ICollection<IComposable> Elements;

    private static Dictionary<string, Func<XmlNode, IComposable>> Parsers = new Dictionary<string, Func<XmlNode, IComposable>>();

    public EventExtensions()
    {
      Elements = new List<IComposable>();
    }

    /// <summary>
    /// Writes this Object to an inline XML Document
    /// </summary>
    /// <param name="xwriter">Valid XMLWriter</param>
    /// <exception cref="System.ArgumentNullException">Thrown if xwriter is null</exception>
    /// <exception cref="EDXLSharp.ValidationException">Thrown if the object fails to validate</exception>
    public void WriteXML(XmlWriter xwriter)
    {
      if (xwriter == null)
      {
        throw new ArgumentNullException("xwriter");
      }

      this.Validate();

      xwriter.WriteStartElement(EDXLConstants.EMEventPrefix, "EventCommunityExtensions", EDXLConstants.EMEventNamespace);
      foreach (IComposable element in Elements)
      {
        element.WriteXML(xwriter);
      }
      xwriter.WriteEndElement();
    }

    /// <summary>
    /// Reads this Object's values from an XML nodelist
    /// </summary>
    /// <param name="rootnode">root XML Node of the Object element</param>
    /// <exception cref="System.ArgumentNullException">Thrown if rootnode is null</exception>
    /// <exception cref="System.ArgumentException">Thrown if the rootnode is not the correct type</exception>
    /// <exception cref="EDXLSharp.ValidationException">Thrown if the object fails to validate</exception>
    public void ReadXML(XmlNode rootnode)
    {
      if (rootnode == null)
      {
        throw new ArgumentNullException("rootnode");
      }

      if (rootnode.LocalName != "EventCommunityExtensions")
      {
        throw new ArgumentException("Unexpted element " + rootnode.LocalName + " instead of EventCommunityExtensions");
      }

      foreach (XmlNode node in rootnode.ChildNodes)
      {
        if (Parsers.ContainsKey(node.LocalName))
        {
          Elements.Add(Parsers[node.LocalName](node));
        }
        else
        {
          XmlEventExtension xee = new XmlEventExtension();
          xee.ReadXML(rootnode);
          Elements.Add(xee);
        }
      }

      this.Validate();
    }

    /// <summary>
    /// Registers a function to parse an <see cref="EDXLSharp.IComposable"/> object
    /// from a given <see cref="System.Xml.XmlNode"/>.
    /// </summary>
    /// <param name="elementName">The name of the element this given function can parse</param>
    /// <param name="parseFunction">A function that can parse the specified element</param>
    public static void RegisterParser(string elementName, Func<XmlNode, IComposable> parseFunction)
    {
      if (string.IsNullOrWhiteSpace(elementName)) //TODO: EventExtension.RegisterParser - Perhaps check if valid XML element name instead?
      {
        throw new ArgumentException("Invalid elementName provided");
      }

      if (parseFunction == null)
      {
        throw new ArgumentNullException("parseFunction");
      }

      Parsers[elementName] = parseFunction;
    }

    /// <summary>
    /// Validates This Message element For Required Values and Conformance
    /// </summary>
    /// <exception cref="EDXLSharp.ValidationException">Thrown if the object fails to validate</exception>
    public void Validate()
    {
      foreach (IComposable element in Elements)
      {
        element.Validate();
      }
    }
  }
}